[Image Source: Phillips, Dustin]
The term “urban heat island” describes a metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. Urban heat islands(UHI) become extremely vulnerable (Coseo and Larsen 2014) when heat and cold waves strike due to its discrepancy in heating and cooling rates and has led to high heat-related mortalities in the past, especially within marginalized communities. This has concerned urban planners, public health officials and policy makers as we are entering an era of increasingly unstable climate. To put this issue in content, we are going to zoom into the supposedly “windy city” Chicago to discuss the impact of UHI over time by analyzing the records from three different weather stations in the city. Based on results of previous studies (Coseo and Larsen 2014), I hypothesize that the temperature trend of the neighborhoods are positively correlated to their distance to downtown and coverage of green infrastructure nearby, including all green area such as parks, gardens and green roofs. We also expect the air temperature during heat waves increases with time in all three stations.
[Fig.1. Urban Heat Islands seem to occur within the city center where the highest concentration of high buildings and industrial area are.Image Source: U.S. Global Change Research Program]
The raw data, including daily maximum and minimum temperature, was provided by National Oceanic and Atmospheric Administration (NOAA) from three weather stations located in three different neighbourhoods of Chicago: Barrington (1962/11/01-2019/02/24), Park forest (1952/09/06-2019/02/12) and Midway airport (1928/02/29-2019/02/23). Each set contains 20,000 to 30,000 days of data. However, not all datasets are complete: there is a gap between 1990 and 2020 in Barrington station. Therefore, the comparison between the three data sets should not be made during that period. The accuracy of collected data could also be compromised based on the set-ups of the stations, especially since this is a research project focused on microclimates within specific neighborhoods.